Re: [PATCH 1/4] drm: add picture aspect ratio flags

Emil Velikov
2016-08-04T14:31:45Z

On 4 August 2016 at 14:15, Sharma, Shashank <shashank.sharma@intel.com> wrote:
> On 8/4/2016 5:04 PM, Emil Velikov wrote:
>>
>> On 4 August 2016 at 11:16, Sharma, Shashank <shashank.sharma@intel.com>
>> wrote:
>>>
>>> Hello Emil,
>>>
>>> Thanks for your time.
>>>
>>> I have got mixed opinion on this.
>>>
>>> IMHO we should expose them to userspace too, as UI agents like Hardware
>>> composer/X/Wayland must know what does these
>>>
>>> flags means, so that they can display them on the end user screen (like
>>> settings menu)
>>>
>>> But few people even think thats its too complex to be exposed to
>>> userspace
>>> agents.
>>>
>> If we want these/such flags passed between kernel and user space one must:
>> - Provide a kernel interface how to do that
>> - Provide a userspace (acked by respective developers/maintainers)
>> that the approach is sane and proves useful.
>>
>> Since the above can take some time, I'd suggest dropping those from
>> the UAPI header(s)... for now.
>>
>> -Emil
>
> Please guide me a bit more on this problem, Emil, Daniel.
> The reason why I want to pass this to userspace is, so that, HWC/X/any other
> UI manager, can send a modeset
> which is accurate upto aspect ratio.
>
Nobody(?) is arguing that you don't to pass such information to/from
userspace :-)
Your series does the internal parsing/management of the attribute and
has no actual UAPI implementation and/or userspace references (to
code/discussions). Thus the UAPI changes should _not_ be part of these
patches.

Daniel's blog [1] has many educational materials why and how things
are done upstream. I would kindly invite you to give them (another?)
courtesy read.

Regards,
Emil

[1] http://blog.ffwll.ch/